Fugitive coloration of textiles



Patented July 13, 1954 FUGITIVE COLORATION OF TEXTILES Lamont Hagan,Clemson, S. 0., assignor to Deering Milliken Research Trust, Pendleton,S. 0., a nonprofit trust of Maine No Drawing. Application December 6,1950, Serial No. 199,547

6 Claims.

This invention relates to the fugitive tinting or coloration oftextiles, more particularly those based on wool, nylon, and othersynthetic fibers, including those which are wholly or partly acrylicpolymers, or esters, but excluding the cellulosic textile materialscontaining cellulose or cellulose derivatives. The invention is alsoapplicable to textile yarns based on blends of wool with suchnon-cellulosic synthetic fibers.

Fugitive coloration of nylon, in particular, pre sents special problemssince the tinted yarn, or fabric woven or knitted therefrom, issubjected to a heat-setting treatment, usually with steam. Thisheat-setting treatment tends to fix the tinting dye more or lesspermanently in the fibers so that the yarns remain stained or colored,and the tint cannot be removed readily in later finishing operations, e.g., the scouring bath. Special reducing or oxidizing treatments toremove the tint are accordingly required. The above, as well as otherfactors, affect the fugitivity of dyes or tints on nylon or other yarnsubjected to heatsetting. Accordingly, it cannot be predicted withcertainty which dyes will be suitable for the fugitive tinting of suchfibers.

In accordance with the present invention, it has been found thatalkaline aqueous solutions of p-nitrophenol are highly suitable forfugitive tinting of wool, of non-ce11ulosic synthetic fibers such asnylon, polyacrylonitrile (Orlon), terephthalic acid ethylene glycolpolymer (Fiber V) and. partially acrylic fibers (Dynel and Chemstrand)and of blends of wool with such synthetic fibers. Thus, for example, asolution such as is obtained by dissolving p-nitrophenol in an aqueoussodium hydroxide solution, whereby the p-nitrophenol is converted intothe sodium salt thereof, will fugitively color nylon a bright yellow,which, even after a steam-setting of the tinted yarn spun therefrom, canbe removed by simply scouring in a soap and water bath. Any color whichdoes not come out in the scouring bath, does so upon treatment of thetinted material with an acidic solution, such as dilute sulfuric acid,hydrochloric acid or acetic acid. The acid media convert the yellowp-nitrophenol sodium salt to p-nitrophenol which is colorless.

A separate acid treatment to remove residual color is not required inthe case of mixtures containing wool which are to be passed through acarbonizing apparatus since the acid employed in the carbonizingprocessing renders any residual tint colorless.

Instead of preparing an alkaline solution of the p-nitrophenol bydissolving p-nitrophenol in sodium hydroxide solution, the sodium saltof the p-nitrophenol can be dissolved in water, and the resulting yellowcolored aqueous solution applied to fugitively tint the non-cellulosicfiber alone or in mixture with Wool.

Among the advantages of p-nitrophenol as a tint is its extremestability; the color does not fade on exposure to air. Yet the tint isreadily removed from the fiber by simply scouring with soap and water,or an acid souring treatment, even if the yarn has been heat-set. Thesodium p-nitrophenolate thus has the advantage of not becoming fixed inthe synthetic fiber, and the further advantage of being readilyremovable, or converted into a colorless compound on treatment with anacid.

A further advantage is that only small amounts of the sodium salt ofp-nitrophenol are required in the tinting solutions to impart sufficienttinctorial properties to clearly stain the synthetic fiber. Thus, forexample, about a 0.3 per cent solution of sodium p-phenolate issuihcient to fugitively color nylon, or other non-cellulosic fibers ormixtures thereof with wool or wool.

- When loose fibers are to be tinted they are merely dipped in orsprayed with the solution of sodium p-nitrophenolate, the excesssqueezed out and the fiber permitted to dry. Yarns can be passed througha bath of the tinting fluid or passed over a wick applicator. Any othersuitable methods may be employed in applying the sodium p-nitrophenolatesolution.

After the tinted fibers or yarns have been processed, the tint is simplyremoved by scouring with soap and water. Any residual stain may beremoved or cleared up by using an acid sour, or in the case of woolblends is removed in the carbonizing treatment to which the tinted woolsynthetic fiber mixtures are usually subjected in the finishing of suchtextiles.

Heretofore, in the case of synthetic fiber wool mixtures, where the woolalone was tinted, during scouring the dye would bleed from the wool ontothe synthetic fiber from which it could not be removed during scouring.When using sodium p-nitrophenolate as the tinctorial agent, any bleedingof this tint from the wool onto the nylon or other synthetic fiberblended with the wool is readily removed in the scouring bath.

The following examples will serve to illustrate the invention:

Example 1 A solution is made up of the following:

3.55 grams of p-nitrophenol 1.02 grams of sodium hydroxide 5.92 grams ofTriton X-100 (an alkylarylpolyether wetting agent) 1172.51 grams ofwater.

The solution has a pH of about 11 and is sufficient to tint 50 pounds ofnylon staple. It is applied to the nylon staple by spraying. In the caseof nylon yarn, the solution is applied by passing the yarn therethroughor over a wick applicator.

Example 2 A solution is made up of:

3.55 grams of sodium p-nitrophenolate 5.92 grams of Triton X-IOO, and1173.53 grams of water.

The tinting solution has a pH of about 11 and is applied in the samemanner as described in Example 1.

Example 3 In the case of tinting non-cellulosic snythetic fiber-blendsor all wool stock, the pH of the tinting solution should not be overabout 8 to avoid the possibility of alkaline damage to the wool. Suchtinting solutions are prepared from the solutions described in Examples1 and 2 by adding thereto sufficient sodium bicarbonate to reduce the pHto about 8. In the case of wool-snythetic fiber blends, the tintingsolutions of about pH 8 are applied dropwise onto a roving of theblends, conveniently at the pin drafter. In the case of 100 per centwool stock, tinting solutions are applied preferably by spraying.

It will be understood that the usual penetrants, lubricants, and sizesmay be included in the tinting bath. The concentration of the sodiump-nitrophenolate may be varied over wide limits. Usually about a 0.3 percent solution is sufficient to provide suflicient tinting coloration.

The following is claimed:

1. A process for the fugitive tinting of organic non-cellulosic textilematerials for purposes of identification during textile operationswherein the tint is capable by scouring of complete removal withoutresidual staining, which process comprises subjecting the textilematerials to an aqueous solution containing sodium p-nitrophenolate.

2. A process as in claim 1 wherein nylon is tinted.

3. A process as in claim 1 wherein a mixed nylon-wool textile is tinted.

4. A process in accordance with claim 1 in which the concentration ofthe sodium p-nitrophenolate in the solution is about at least 0.3%.

5. A process for fugitive tinting of textile materials for purposes ofidentification during textile operations wherein the tint is capable byscouring of complete removal Without residual staining which processcomprises dissolving pnitrophenol in an aqueous solvent containingsodium hydroxide, and tinting an organic noncellulosic textile materialwith the resulting yellow colored solution.

6. A process as in claim 5 wherein nylon is tinted.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,341,423 Catlin Feb. 8, 1944 FOREIGN PATENTS Number CountryDate 553,442 Great Britain May 21, 1943 OTHER REFERENCES Rowes ColourIndex, published by Society Dyers & Colorists, London, 1st ed, 1924,pages 1, 1, 2, 2.

Organic Dyestuffs, by A. Wahl, translated by Atack, published in London,1914, by G. Bell & Sons, pages 85, 86, 87.

Amer. Dyestuff Reporter for July 30, 1945, page 304.

Silk Jour. and Rayon World for August 1945, p. 33.

1. A PROCESS FOR THE FUGITIVE TINTING OF ORGANIC NON-CELLULOSIC TEXTILEMATERIALS FOR PURPOSES OF IDENTIFICATION DURING TEXTILE OPERATIONSWHEREIN THE TINT IS CAPABLE BY SCOURING OF COMPLETE REMOVAL WITHOUTRESIDUAL STAINING, WHICH PROCESS COMPRISES SUBJECTING THE TEXTILEMATERIALS TO AN AQUEOUSL SOLUTION CONTAINING SODIUM P-NITROPHENOLATE.